Claripy is an abstracted constraint-solving wrapper.
Project repository: https://github.com/angr/claripy
Documentation: https://api.angr.io/projects/claripy/en/latest/
It is usable!
General usage is similar to Z3:
>>> import claripy
>>> a = claripy.BVV(3, 32)
>>> b = claripy.BVS('var_b', 32)
>>> s = claripy.Solver()
>>> s.add(b > a)
>>> print(s.eval(b, 1)[0])